Fuel delivery systems for internal combustion engines are available in many different varieties. One of the more common of which is the port fuel injection system. The port fuel injection system utilizes a plurality of fuel injectors each of which delivers a predetermined amount of fuel to the inlet port of an associated combustion chamber. In such systems, the fuel injectors are mounted in sockets or injector bosses of a manifold or fuel rail, which operates to communicate fuel to each of the injectors.
Recent advances in fuel delivery and combustion research has allowed direct injection, or DI, fuel delivery systems to increase in popularity. The DI fuel delivery system provides a fuel injector within the cylinder head of the internal combustion engine. The DI fuel injector operates to inject a predetermined amount of fuel directly into the combustion chamber. Since the gas pressure within the combustion chamber is orders of magnitude greater than that of the intake port, the DI fuel rail and fuel injector operate at a much higher fuel pressure than similar components within the port fuel injection system. The DI fuel delivery system enables higher peak power levels, improved fuel economy, and lower emissions. These beneficial aspects of the DI fuel delivery system are a result of the precise metering of the fuel injected into the combustion chamber as well as improved intake airflow into the combustion chamber.
The electromagnetic fuel injectors of the DI fuel delivery system deliver fuel to the combustion chamber in metered pulses, which are timed to control the amount of fuel delivered and to coordinate such delivery with specific points of the operational cycle of the engine. The sequential energization of the fuel injectors may operate to induce pressure pulsations within the fuel rail, which may produce noise-emitting vibrations. The transmission of vibrational energy generated within the DI fuel delivery system to the engine structure may follow two paths; from the fuel injector to the cylinder head and from the fuel rail to the respective attachment point, which is most likely the cylinder head.